Redo "Use an explicit 'this' parameter instead of 'This' nodes."

pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart_tree_printer;
 
 import '../constants/values.dart' as values;
 import '../dart_types.dart' as types;
 import '../dart2jslib.dart' as dart2js;
 import '../elements/elements.dart' as elements;
@@ skipping 380 matching lines @@
       }
       result = new tree.Send(
           receiver,
           selector,
           argList(exp.arguments.map(makeArgument)));
       if (callee is Identifier) {
         setElement(result, element, exp);
       }
     } else if (exp is CallMethod) {
       precedence = CALLEE;
-      tree.Node receiver = exp.object is This
-          ? null
-          : makeExp(exp.object, PRIMARY, beginStmt: beginStmt);
+      // TODO(sra): Elide receiver when This, but only if not in a scope that
+      // shadows the method (e.g. constructor body).
+      tree.Node receiver = makeExp(exp.object, PRIMARY, beginStmt: beginStmt);
       result = new tree.Send(
           receiver,
           makeIdentifier(exp.methodName),
           argList(exp.arguments.map(makeArgument)));
     } else if (exp is CallNew) {
       precedence = CALLEE;
       tree.Node selector = makeName(exp.type.name);
       if (exp.type.typeArguments.length > 0) {
         selector = new tree.TypeAnnotation(
             selector,
@@ skipping 24 matching lines @@
     } else if (exp is Conditional) {
       precedence = CONDITIONAL;
       result = new tree.Conditional(
           makeExp(exp.condition, LOGICAL_OR, beginStmt: beginStmt),
           makeExp(exp.thenExpression, EXPRESSION),
           makeExp(exp.elseExpression, EXPRESSION),
           question,
           colon);
     } else if (exp is FieldExpression) {
       precedence = PRIMARY;
-      tree.Node receiver = exp.object is This
-          ? null
-          : makeExp(exp.object, PRIMARY, beginStmt: beginStmt);
+      // TODO(sra): Elide receiver when This, but only if not in a scope that
+      // shadows the method (e.g. constructor body).
+      tree.Node receiver = makeExp(exp.object, PRIMARY, beginStmt: beginStmt);
       result = new tree.Send(receiver, makeIdentifier(exp.fieldName));
     } else if (exp is ConstructorDefinition) {
       precedence = EXPRESSION;
       tree.NodeList parameters = makeParameters(exp.parameters);
       tree.NodeList initializers =
           exp.initializers == null || exp.initializers.isEmpty
           ? null
           : makeList(",", exp.initializers.map(makeExpression).toList());
       tree.Node body = exp.isConst || exp.body == null
           ? new tree.EmptyStatement(semicolon)
@@ skipping 872 matching lines @@
             printStringChunk(chunk.previous),
             node);
       } else {
         return node;
       }
     }
     return printStringChunk(output.chunk);
   }
 
 }